Generally, manufacturing steps of semiconductors, MEMS, etc., involve etching silicon wafers by using etching solutions. As a method of etching the silicon wafer by the etching solution, alkaline etching that uses an aqueous alkaline solution of, for example, potassium hydroxide (KOH) or tetramethyl ammonium hydroxide (TMAH) has widely been used.
Relevant existent techniques, for example, JP5-94975A and JP9-246254A are cited herein.
The alkaline etching has been performed by supplying an alkaline chemical solution to a central portion of a wafer while holding and rotating the wafer in a sheet type cleaning machine. However, when the alkaline chemical solution is supplied from the central portion of the wafer, the amount of etching is sometimes different between the central portion and a peripheral edge portion of the wafer.
The present invention has been accomplished in view of the foregoing and intends to provide a substrate processing method capable of allowing the amount of etching to be uniformly applied over the area ranging from the central portion to the peripheral edge of the wafer, a substrate processing apparatus, and a storage medium.